Amplifier for sound-reproducing machines



May 29, 1923.;

P. RADDIS AMPLIFIER FOR SOUND REPRODUGING MACHINES Filed Feb/2s. 1922 2 Sheets-Sheet 1 May 29, 1923.

P. RADDIS AMPLIFIER FOR SOUND REPRODUCING MACHINES Filed Feb. 25. 1922 2 Sheets-Sheet 2 naw/14 507, dd

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Patented May 29, 1923.

PATENT OFFICE.

PAUL BADDIS, OF MIAMI, OKLAHOMA,

AMPLIFIER FOR SOUND-REPRODUOING MACHINES.

Application filed February 23, 1922. Serial No. 538,794.

To ZZZ wkom'it may concern: Be it known that 1, PAUL RADDIs, a c1t1- zen of the United States, residing at Miami,

in the county of Ottawa and State of Oklahoma, have invented certain new and usefullmprovements in Amplifiers for Sound- Reproducing Machines; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to an improved am plifier or horn for sound reproducing machines, and it has for its principal aim to provide an amplifier of this class which is such in construction as to act as a resonator for decidedly affecting the quality of the tones reproduced to an extent to deaden or mute undesirable scraping and scratching noises and reinforcing the vibrations to produce. clear and harmonious tones.

I aim to construct a horn or amplifier of suitable design and shape fromspecified pieces of wood treated in away to permit them to retain their natural or inherent I tone resonating and amplifying qualities and'obviating the necessityof bending and treating the wood by methods now utilized which seem to be detrimental to the production of mellow and clear tones.

More specifically speaking, it is one of the objects of the inventionto produce an amplifier or resonator wherein the sides, of which there are a number, are sawed into shape instead of being bent and are formed from different kinds of wood and permitted to be dried in'the air so as to prevent any of the natural tone-reinforcing and resonating qualities from being extracted therefrom.

It is another object of the invention to produce an amplifier formed from a number of sides having portions arranged in abutting relation, these portions being mainl secured together by strips of fabric materlal to obviate the necessity of utilizing mechanical fastenings which tend to affect v and mute the tones.

amplifier constructed in accordance with this invention.

Figure 2 is a top plan view thereof.

Figure 3 is a section taken on the line of Fig. 1.

Figure l is a central longitudinal sectio nal view through the amplifier.

Figure 5 is a section taken substantially on the plane of the line 5-5 of Fig. 4c.

4 Figures 6 and 7 are sections taken on the lines 6-6 and 77 respectively of Fig. 4.

In carrying out the invention, I make use of a horn or amplifier which is shaped approximately the same as those now employed by a conventional form of sound reproducing machine. As a matter of fact, however, the shape and size of the amplifier is not altogether material in so far as the real novelty of the invention is concerned.

From the foregoing it will be seen that the preferred form of the horn is polysided, the sameeinbodying afiat and horizontally disposed bottom 1, outwardly flaring and longitudinally curved side walls 2 and an upwardly curved top wall 3. These walls constitute the horn proper. Associated with this horn is a depending throat which is substantially square in cross section, this throat being engaged with the reduced or small end of the horn in any suitable manner so as not to interfere with the equal and uniform distribution of the sound waves. The throat comprises fiat parallel sides at, longitudinally curved top and bottom walls 5 and 6 respectively and straight front and rear walls 7 and 8 respectively. As before indicated, the throat may be connected with the horn in any suitable way and in the showing a telescopic connection is provided. To produce this connection, the aforesaid side walls l of the throat are simply extended beyond the top and bottom walls 5 and 6 so as to permit the reduced end of the horn to be snugly received between them. The inner faces of these extensions are cut out as at 9 (see Fig. 6) so as to permit the inner faces of the side walls of the horn to lie flush with the corresponding faces of the side walls of th throat. Experience has taught that the use of metallic fastenings for the sides or walls of amplifiers or the like tends to deaden the tone quality to a certain extent and to overcome this objection I use a small portion of glue to secure the meeting portions of the various walls, but the amount or" glue em ployed is not sutlicient to properly retain the walls in their respective positions nor to atfect the quality of the tone. To act in conjunction with the glue I utilize narrow strips of fabric 10 and glue these to the corners of the Walls of the throat and horn. Fastening means of this character has been found not to render the tone detective and objectionable.

As before indicated, the results sought are obtained by making use of select kinds of wood for cooperation with one another. Many experiments have been made and an amplifier has been provided which will produce the results hereinbetore mentioned. In carrying out this end, I do not bend any parts of the throat or horn, but saw them into the particular shape desired and shown. Ordinariy, wood for forming amplifiers is treated through a process 01 steaming in order to cause the walls to maintain the curved or particular shapes given them. It has been found that the process of treating the Wood is decidedly detrimental to the tone quality. However, by sawing the wood into the desired shape and permitting it to be air dried none of the natural tone producing qualities of the wood are removed. Consequently, an extremely etiicient and desirable resonator is produced which will decidedly amplify the sound waves and will tend to eliminate, to a certain extent, much of the undesirable scratching noises. The

actual horn to which reference has been made amplifies the sound waves to a very noticeable extent due to the fact that the kinds of wood employed are easily susceptible to Vibration. WVhile it is not essential, the curved side walls 2 of the horn or amplifier, are formed of walnut, wherein the grain runs vertically, these being sawed out as before indicated to obviate the necessity of bending them. The flat horizontal bot tom 1 is formed of second growth walnut While the curved top is formed of black Walnut and the grain in the latter wall preferably runs straight. Referring also to the throat it will be seen that the curved top and bottom pieces and 6 are also sawed into shape, the same being of uniform thickness and the first named being composed of black walnut while the remaining wall is preterably wild cherry, the grain in both of these walls running at an approximate degree angle. The pieces 7 and S of the throat are preferably made of wild cherry wood and the grain is vertical. Although it is not shown, the tone arm which is designed for co-action with the throat and horn is likewise to be composed of wood which is se lected and treated in the aforesaid manner.

By carefully considering the description connection with the drawings, persons .iliar with devices of this class will doubtless be able to obtain a clear understanding of the invention. Therefore, a more lengthy and detailed description is deemed unnecessa-ry.

time probably the best results may be obtained with the construction and arrangement herein shown and described, this is taken as the preferred embodiment of the invention. However, I wish it to be understood that minor changes coming within the scope of the invention as claimed may be re sorted to if desired.

I claim:

Lin amplifier for sound reproducing machines comprising a forwardly flaring horn termed of a plurality of walls, a depending throat telescopically connected with the inner reduced end of the horn, said throat be ing composed of separate walls, and strips of fabric extending along the corners of the horn and throat and connected with the walls :tor simultaneously connecting the "ails with one another and for connecting the horn to the throat.

In testimony whereof I have hereunto set my hand.

PAUL RADDIS. 

